1. Field of the Invention
The present invention relates to an X-ray diagnostic apparatus and, more particularly, an X-ray diagnostic apparatus which is able to make various positionings in a single apparatus by providing a second C-shaped arm along an inner periphery of a first C-shaped arm such that slide operations of respective C-shaped arms can be controlled individually and is also able to be used like an X-ray CT apparatus.
2. Description of the Related Art
Conventional apparatus include a stationary X-ray diagnostic apparatus (stationary holding apparatus) shown in FIG. 1.
The stationary holding apparatus comprises a ceiling fitting portion 50 fitted to a ceiling, a holding arm 51 whose one end is held by the ceiling fitting portion 50 such that its strut can be rotated, a C-shaped arm holder 52 provided to the other end of the holding arm 51 such that its main shaft can be rotated, and holding a substantially C-shaped arm 53 slidably, and an image intensifier (I.I.) 55 and an X-ray generator 54 provided to both ends of the C-shaped arm 53 respectively so as to oppose to each other.
As the arm shape, if roughly classified, there have been known a C-type which is the arm shape of the C-shaped arm 53, and a U-type which is the U-shaped arm. In addition, as a method of holding the C-shaped arm, there have been known a C-shaped holding method wherein the C-shaped arm is held by a C-shaped arm holder which can be rotated around an axis provided in parallel to the floor and the ceiling, an .OMEGA.-shaped holding method wherein the C-shaped arm is held by the C-shaped arm holder which is fitted to the ceiling rotatably around an axis provided vertically to the floor and the ceiling, etc. Today, from the viewpoint of three-dimensional positioning which makes it possible to make various positionings of an X-ray generation/detection system according to cases of the disease, the C-shaped holding method has become the mainstream.
A rail is provided to the C-shaped arm 53. The C-shaped arm 53 is held slidably by putting the rail of the C-shaped arm 53 between holding rollers which are provided to the C-shaped arm holder 52.
A movement driver 56 which can move and control the I.I. 55 forward and backward (an X-ray generator 54 side and an opposite side to the X-ray generator 54) is provided to the C-shaped arm 53. Movement control executed by the movement driver 56 can cause the I.I. 55 to move forward/backward via an opening portion provided in the C-shaped arm 53.
The stationary holding apparatus can set the C-shaped arm 53 to a desired position by virtue of strut rotation, main shaft rotation, sliding movement, etc. A small amount of X-ray is irradiated from the X-ray generator 54 at the time of radioscopic operation, whereas a large amount of X-ray is irradiated from the X-ray generator 54 at the time of image picking-up operation. The I.I. 55 can convert X-ray information transmitted through a subject into optical information and then converge such optical information into a TV camera via an optical lens. As a result, radioscopic images or picked-up images can be displayed on a monitor device, etc.
Here, a direction of angle setting to the subject will be defined. As shown in FIG. 2, the term "RAO (Right Anterior Oblique position)" signifies an oblique position wherein a right front side of the subject is directed to a film (imaging device) side, and the term "LAO (Left Anterior Oblique position)" signifies an oblique position wherein a left front side of the subject is directed to the film (imaging device) side. Then, the term "CAU (Caudal)" signifies a position wherein a foot side of the subject is directed to the film (imaging device) side, and the term "CRA (Cranial)" signifies a position wherein a head side of the subject is directed to the film (imaging device) side. Such stationary holding apparatus can be used as a cardiac positioner (Cardiac) or a general positioner (General). If the stationary holding apparatus is used as the cardiac positioner, images of the subject (radioscopic images or picked-up images) are picked up after the subject has been inserted from his or her head first since setting of wide angle with respect to the main axes (RAO/LAO) is needed.
More particularly, the angle setting necessary for clinic by the cardiac positioner is that RAO/LAO are about 120.degree./120.degree. and CRA/CAU are about 45.degree./45.degree.. Normally, if the subject is inserted from his or her head first, limit rotatable ranges of the stationary holding apparatus are about 180.degree./180.degree. in the RAO/LAO and about 45.degree./90.degree. in the CRA/CAU because of its structure. If the case is considered where the subject is accessed from the left lateral side, the rotatable ranges of RAO/LAO become 90.degree./45.degree. and the rotatable ranges of CRA/CAU become 180.degree./180.degree.. For this reason, respective angle settings of 45.degree. to 120.degree. in LAO and 90.degree. to 120.degree. in RAO, which are required for the cardiac positioner, cannot be accomplished.
In addition, if an offsetless positioner is employed as the cardiac positioner, when a top plate of a bed is slid to the head side of the subject, a slide stroke to an inguinal region of the subject cannot be assured since a top plate of the C-shaped arm interferes with the top plate of the bed. In the case of cardiac blood vessel inspection, it is common that the catheter is inserted from the inguinal region and thus an inguinal radioscopy is an indispensable function for the cardiac positioner. In addition, an anesthetist usually tends to stand on the head side of the subject.
Therefore, if the stationary holding apparatus is employed as the cardiac positioner, an offset positioner is employed from the viewpoint of the inguinal radioscopy (wide angle setting) and the operation space of the anesthetist, so that images of the subject are to be picked up after the subject has been inserted from his or her head first.
Alternatively, if the stationary holding apparatus is used as the general positioner, the offsetless positioner is employed since there is necessity of accessing freely the subject from head to foot, so that images of the subject are picked up after the subject has been inserted laterally, i.e., crossfeed of the subject has been executed.
Because both the offset cardiac positioner and the offsetless general positioner are needed to execute precise diagnosis and therapy of the subject, a composite system is constructed in the prior art by installing respective positioners in one room, so that diagnosis and therapy of the subject can be executed by employing respective positioners in combination.
On the contrary, in an IVR (Interventional Radiology) using the X-ray diagnostic apparatus including such stationary holding apparatus, effectiveness of a combined inspection which employs not only normal blood vessel picked up images but also lateral sectional images collected by the X-ray CT apparatus has been appreciated up to now.
If the X-ray CT apparatus is employed in combination, normally an angio room into which the X-ray diagnostic apparatus is installed and a CT room into which the X-ray CT apparatus is installed are provided as a separate room respectively. Therefore, in this combined inspection, the subject must be laid on a stretcher and then be transferred to respective rooms. However, it has been troublesome to transfer the subject and in addition there has been such a fear that the catheter comes out during the transfer of the subject, etc.
Therefore, in order to enable the combined inspection, both the X-ray diagnostic apparatus and the X-ray CT apparatus are installed in one room, and then the bed is slid toward the X-ray diagnostic apparatus if the images are to be picked up by the X-ray diagnostic apparatus while the bed is slid toward the X-ray CT apparatus if the images are to be picked up by the X-ray CT apparatus. In this manner, such combined inspection can be carried out by using one bed commonly for both the X-ray diagnostic apparatus and the X-ray CT apparatus.
As a consequence, without transfer of the subject between the room in which the X-ray diagnostic apparatus is installed and the room in which the X-ray CT apparatus is installed, the combined inspection can be performed by sharing one bed, so that troublesome transfer of the subject can be omitted. In addition, such a disadvantage can be prevented that the catheter comes out during transfer of the subject.
However, as shown by a reference 55a in FIG. 1, an optical system 55a of the I.I. 55 is projected from the C-shaped arm 53 outwardly in the X-ray diagnostic apparatus in the prior art. Therefore, if the C-shaped arm 53 is controlled to be slid in the CAU direction or the CRA direction, the optical system 55a of I.I. 55 interferes with the C-shaped arm holder 52. Furthermore, if the over-tube positioning which positions the X-ray generator 54 on the ceiling side is taken, the optical system 55a of the I.I. 55 interferes with the floor plate 57. In this fashion, there has been a problem that the positioning is restricted.
Besides, since the offset positioner is needed as the cardiac positioner and the offsetless positioner is needed as the general positioner, both positioners must be prepared respectively to execute precise diagnosis of the subject, etc. Therefore, there has been another problem that a burden of installing area to the hospital side and an economic burden are increased.
Moreover, three dimensional techniques which make images of complicated vessel spread stereoscopically and used in diagnosis/therapy have been tried according to various modalities. However, in the X-ray diagnostic apparatus, there has been still another problem that three dimensional images, as have been picked up by the X-ray CT apparatus and the MR apparatus, cannot be realized because of the above restriction of positioning.
In other words, as the X-ray diagnostic apparatus at present, such an apparatus has been known that can get the start/stop data by rotational DSA (Digital Subtraction Angiography) and can thus acquire image information over the wider angular range. However, necessary and sufficient information of the image have not been acquired yet to form three dimensional images. Hence, images of complicated vessel spread have not made stereoscopically still yet.
In the rotational DSA, the start/stop data can be taken and also the image information can be acquired over the wider angular range. However, there has been yet still another problem that irradiation timing of X-ray is complicated and that the artifact is caused in the reproduction image by variation in speed at the time of start/stop to thus degrade reproducibility, and the like.
On the contrary, in the case of the IVR wherein the X-ray CT apparatus is used in combination, picking-up of the image must be switched by transferring the bed on which the subject is laid down between the X-ray diagnostic apparatus and the X-ray CT apparatus. However, there has been additional problem that quick switching of image picking-up cannot be realized since it takes a lot of times to transfer the bed. Also, it has been a fear that pulling-out of the catheter is caused because of such transfer of the bed.